US9017289B2 - Transdermal fluid delivery device - Google Patents

Abstract

A transdermal fluid delivery device includes a housing defining a longitudinal axis and having a proximal end and a distal end. The housing defines a passageway extending longitudinally therethrough. A fluid reservoir is disposed at the proximal end of the housing in communication with the passageway of the housing and is adapted for retaining a fluid therein. A base member is positioned at the distal end of the housing. A microneedle assembly including a plurality of microneedles extending distally therefrom is also provided. The microneedle assembly is selectively moveable with respect to the housing between a retracted position, wherein the microneedles are disposed within the housing, and an extended position, wherein the microneedles are advanced distally to penetrate the base member and extend distally therefrom for puncturing the patient's epidermis and delivering the fluid into the patient's bloodstream.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/409,690, filed on Nov. 3, 2010, the entire contents of which are hereby incorporated by reference herein.

BACKGROUND

1. Technical Field

The present disclosure relates generally to devices for transdermal fluid delivery of medicaments. More particularly, the present disclosure relates to micro-needle array patches for transdermal fluid delivery of drugs and/or nutrients.

2. Background of the Related Art

Transdermal fluid delivery of drugs is an effective and convenient way for patients to receive medications and/or nutrients. Transdermal fluid delivery of drugs is particularly useful where a patient needs to maintain a continuous level of medication in the blood stream over an extended period of time, where the patient is likely to forget to take medication or has difficulty taking medication orally, and/or where the patient is unable to properly absorb the medications or nutrients through the digestive system. However, not all drugs and nutrients are easily absorbed through the epidermis. For example, the molecules of the drugs or nutrients may be too large, the drugs or nutrients may be too lipophobic, and/or the required dose may be too large to be efficiently absorbed by the epidermis.

More recently, transdermal patches including micro-needle arrays have been used to puncture the epidermal layer to deliver drugs and/or nutrients into the blood stream, circumventing some of the limitations associated with absorbing the drugs and/or nutrients through the epidermis. However, when these micro-needle arrays are removed from the patient's epidermis, the punctures created by the needles, if not properly protected, provide a potential avenue for the introduction of virus and bacteria into the blood stream. Additionally, if the needles are not properly maintained prior to insertion, virus and/or bacteria on the needles themselves may infect the patient upon insertion of the micro-needle array.

For example, U.S. Pat. No. 7,226,439 discloses a microneedle drug delivery device including a reservoir and a substrate having one or more microneedles attached thereto and extending therefrom. The reservoir is selectably connectable to the substrate such that the reservoir contents can flow from the reservoir out through the tips of the microneedles. In use, the microneedles are inserted into the skin, while the substrate is retained in position on the skin by an adhesive. The reservoir may then be connected to the substrate for delivering the drugs to the patient. At the completion of treatment, the substrate is removed from the patient's skin, leaving behind a plurality of open puncture wounds where the microneedles were inserted. These unprotected, open puncture wounds are susceptible to disease and/or infection. Further, there is the risk that the exposed microneedles may become contaminated prior to insertion into the patient's skin, putting the patient at risk of disease and/or infection.

SUMMARY

In accordance with the present disclosure, a transdermal fluid delivery device is provided. The transdermal fluid delivery device is positionable on a patient's epidermis for delivering fluid into the patient's bloodstream. The transdermal fluid delivery device includes a housing defining a longitudinal axis and having a proximal end and a distal end. The housing defines a passageway extending longitudinally therethrough. A fluid reservoir is disposed at the proximal end of the housing in communication with the passageway. The fluid reservoir is adapted to retain a fluid, e.g., drugs and/or nutrients, therein. A base member is positioned at the distal end of the housing. A microneedle assembly including a plurality of microneedles extending distally therefrom is initially disposed within the housing. The microneedle assembly is selectively moveable with respect to the housing between a retracted position, wherein the microneedles are disposed within the housing, and an extended position, wherein the microneedles are advanced distally to penetrate the base member and extend distally therefrom. In the extended position, the microneedles are adapted for puncturing the patient's epidermis to deliver fluid into the patient's bloodstream.

In one embodiment, at least a portion of the housing is rotatable with respect to the microneedle assembly about the longitudinal axis of the housing between a first position and a second position for moving the microneedle assembly between the retracted position and the extended position. More specifically, a helical cam surface may be formed on an inner surface of the portion of the housing and the microneedle assembly may include one (or more) protrusions engaged with the cam surface such that, upon rotation of the portion of the housing with respect to the microneedle assembly, the protrusions travel along the helical cam surface, translating the microneedle assembly longitudinally with respect to the housing.

In another embodiment, a latching mechanism may be included for retaining the microneedle assembly in the retracted position and/or the extended position. Further, the microneedle assembly may be biased towards the retracted position or the extended position.

In yet another embodiment, the microneedle assembly is longitudinally translatable with respect to the housing between a first position and a second position for moving the microneedle assembly between the retracted position and the extended position.

In still another embodiment, the microneedle assembly includes a first latch member and the housing includes a second, complementary latch member such that, upon movement of the microneedle assembly to the extended position, the first and second latch members engage one another to retain the microneedle assembly in the extended position.

In still yet another embodiment, one (or both) of the first and second latch members defines a pre-determined latching period. Accordingly, the latch member may be configured to disengage the other latch member at the end of the pre-determined latching period such that the microneedle assembly is permitted to return to the retracted position.

In yet another embodiment, a skin adhesive is disposed on a distal surface of the base member for adhering the housing to the patient's epidermis. A peelable cover may be disposed over the skin adhesive to preserve the skin adhesive and to inhibit adhesion prior to use.

In still another embodiment, when the microneedle assembly is moved to the extended position, the microneedles are configured to extend distally from the base member by about 2 mm to about 3 mm. Further, the microneedles may include pointed distal ends to facilitate penetrating the base member and/or puncturing the patient's epidermis.

Another embodiment of a transdermal fluid delivery device provided in accordance with the present disclosure includes a housing, a fluid reservoir, a base member, and a microneedle assembly. The housing defines a longitudinal axis and includes a proximal end and a distal end. The housing also defines a passageway extending longitudinally therethrough and a helical cam track formed on an inner surface thereof. The housing is rotatable between a first position and a second position. The fluid reservoir positionable within the passageway of the housing and is adapted to retain a fluid therein. The base member is positioned at the distal end of the housing. The microneedle assembly is coupled to the fluid reservoir and includes a plurality of microneedles extending distally therefrom. The microneedle assembly including at least one protrusion extending therefrom that is configured to engage the cam track of the housing such that, upon rotation of the housing between the first and second positions, the microneedle assembly is translated longitudinally relative to the housing between a retracted position, wherein the microneedles are disposed within the base member, and an extended position, wherein the microneedles extend distally from the base member for puncturing the patient's epidermis and delivering the fluid into the patient's bloodstream. The transdermal fluid delivery device may further be configured similarly to any of the embodiments above.

Another embodiment of a transdermal fluid delivery device provided in accordance with the present disclosure includes a housing, a fluid reservoir, a base member, and a microneedle assembly. The housing defines a longitudinal axis and includes a proximal end, a distal end, and a passageway extending longitudinally therethrough. The fluid reservoir is positionable within the passageway of the housing and is adapted to retain a fluid therein. The base member is positioned at the distal end of the housing. The microneedle assembly is coupled to the fluid reservoir and includes a plurality of microneedles extending distally therefrom. The microneedle assembly is longitudinally translatable with respect to the housing between a retracted position, wherein the microneedles are disposed within the base member, and an extended position, wherein the microneedles extend distally from the base member for puncturing the patient's epidermis and delivering the fluid into the patient's bloodstream. The transdermal fluid delivery device may further be configured similarly to any of the embodiments above.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of the present disclosure are described herein below with reference to the drawings, wherein:

FIG. 1 is a side, cross-sectional view of one embodiment of a transdermal fluid delivery device in accordance with the present disclosure, shown with parts separated;

FIG. 2 is a side, cross-sectional view of the transdermal fluid delivery device ofFIG. 1 shown disposed in a retracted position;

FIG. 3 is a side, cross-sectional view of the transdermal fluid delivery device ofFIG. 1 shown disposed in an extended position;

FIG. 4 is a side, cross-sectional view of another embodiment of an transdermal fluid delivery device in accordance with the present disclosure, shown with parts separated;

FIG. 5 is a side, cross-sectional view of the transdermal fluid delivery device ofFIG. 4 shown disposed in the retracted position; and

FIG. 6 is a side, cross-sectional view of the transdermal fluid delivery device ofFIG. 4 shown disposed in the extended position.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Various embodiments of the present disclosure and methods of using the same will now be described in detail with reference to the drawings wherein like references numerals identify similar or identical elements. In the drawings, and in the following description, the term “proximal” should be understood as referring to the end of the device, or component thereof, that is closer to the clinician during proper use, while the term “distal” should be understood as referring to the end that is farther from the clinician, as is traditional and conventional in the art.

Referring now toFIG. 1, one embodiment of a transdermal fluid delivery device in accordance with the present disclosure is show identified byreference numeral100. Transdermalfluid delivery device100 generally includes afluid reservoir110, ahousing120, amicroneedle assembly130, and abase140.Fluid reservoir110 is engaged tomicroneedle assembly130 and, upon actuation, is in fluid communication withmicroneedle assembly130 such that fluid “F” fromfluid reservoir110 may flow throughmicroneedle assembly130 for transdermal fluid delivery of the fluid “F” to a patient.Housing120 includes aframe122 and arotatable collar124.Housing120 is disposed aboutfluid reservoir110 andmicroneedle assembly130 and defines a longitudinal axis “X.”Base140 is engaged to frame122 ofhousing120 at adistal end123athereof and is configured for positioning on a patients skin to retain transdermalfluid delivery device100 thereon. As will be described in greater detail below,microneedle assembly130 is axially translatable, upon rotation ofcollar124 ofhousing120, between an initial, retracted position (FIG. 2), whereinmicroneedle assembly130 is fully disposed withinrotatable collar124, and an extended position (FIG. 3), whereinmicroneedle assembly130 extends at least partially fromrotatable collar124 and throughbase140 in a distal direction, e.g., to penetrate the patient's skin.

Fluid reservoir110 is adapted to retain a fluid “F,” e.g., medicaments, nutrients, or other treatment fluids, therein for delivery to the patient.Fluid reservoir110 is disposed at a proximal end ofmicroneedle assembly130 and is sealingly engaged thereto. More specifically,fluid reservoir110 includes a rigid, orsemi-rigid seal ring112 disposed at adistal end113 thereof for sealingly engaginghub132 ofmicroneedle assembly130. Further, a penetrable membrane or other barrier (not shown) may be disposed betweenfluid reservoir110 andhub132 ofmicroneedle assembly130 to inhibit fluid “F” from passing distally fromfluid reservoir110 intomicroneedle assembly130 prior to actuation. The penetrable membrane (not shown) may be penetrated to permit the passage of fluid “F” therethrough upon movingmicroneedle assembly130 from the retracted position (FIG. 2) to the extended position (FIG. 3), e.g., via the rotation ofcollar124, or, in embodiments wherefluid reservoir110 is elastomeric, upon depression offluid reservoir110. Alternatively, any other suitable mechanism may be provided for penetrating the penetrable membrane (not shown). It is also envisioned that a selectively controlled barrier (not shown) may be provided, allowing the user to selectively permit/inhibit the flow of fluid “F” fromfluid reservoir110 intohub132 ofmicroneedle assembly130.

With continued reference toFIG. 1,fluid reservoir110 may define a dome-like configuration whereinseal ring112 is disposed atdistal end113 offluid reservoir110 and defines the base portion offluid reservoir110 and whereinproximal end114 offluid reservoir110 defines the apex portion of the dome-shapedreservoir110. Further,fluid reservoir110 may be formed from any suitable bio-compatible material, e.g., polymeric materials or, more specifically, elastomeric materials. It is also envisioned thatfluid reservoir110 be non-porous, to inhibit gas from penetrating therethrough or loss of fluid “F.” Such a feature is particularly useful where the drugs or nutrients contained withinfluid reservoir110 are sensitive to oxygen, for example, or other gases. In embodiments wherefluid reservoir110 is formed from an elastomeric material,fluid reservoir110 may be biased toward a collapsed state, such that the “F” fluid withinfluid reservoir110 is urged, or biased distally towardmicroneedle assembly130 to facilitate delivery of the fluid “F” intomicroneedle assembly130 and, eventually, to the patient. Such a configuration is particularly useful where the drugs and/or nutrients to be delivered are more viscous, or where the fluid “F” contains suspended particles therein. In either configuration, it is envisioned thatfluid reservoir110 be capable of withstanding rubbing, bumping, brushing, and/or other typical external forces acting onfluid reservoir110, such that thefluid reservoir110 does not puncture or rupture during use. The particular size, volume and configuration offluid reservoir110 may be determined, for example, by the amount of fluid to be delivered, the time frame for delivery, and/or the specific properties of the fluid to be delivered.

As mentioned above,housing120 includes aframe122 and arotatable collar124.Frame122 defines an annular, or ring-like configuration including aproximal end123b, adistal end123aand a passageway, or lumen extending therethrough.Rotatable collar124 is positioned withinframe122 and similarly defines an annular, or ring-like configuration including aproximal end125b, adistal end125aand a passageway, or lumen extending therethrough.Housing120 may be formed from any suitable bio-compatible material, e.g., polymeric materials. Aninner surface126 ofrotatable collar124, which defines the lumen extending therethrough, may include a helical ramp, orcam track127 defined therein.Helical cam track127 is positioned about longitudinal axis “X” and defines a pre-determined pitch, or slope. As will be described in greater detail below,cam track127 is configured to retainhub132 ofmicroneedle assembly130 therein such that, upon rotation ofrotatable collar124 about longitudinal axis “X,”hub132 ofmicroneedle assembly130 is moved, or cammed alongcam track127, translatingmicroneedle assembly130 longitudinally with respect tohousing120 according to the pre-determined pitch ofhelical cam track127.Rotatable collar124 may further include aflange128 positioned on an outercircumferential surface129 thereof and extending radially outwardly therefrom through a slot (not explicitly shown) defined withinframe122 ofhousing120 to facilitate rotation ofcollar124 with respect tomicroneedle assembly130 and/or to provide a visual indication as to the relative positioning ofcollar124 with respect tomicroneedle assembly130.

As shown inFIG. 1,microneedle assembly130 includes aproximal hub132 having a plurality ofmicroneedles134 extending distally therefrom.Hub132 includes a pair ofprotrusions137 extending radially outwardly therefrom at opposite sides thereof.Protrusions137 are engaged withincam track127 defined withininner surface126 ofcollar124 to facilitate longitudinal translation ofmicroneedle assembly130 with respect tocollar120 upon rotation ofcollar124 about longitudinal axis “X.” In other words,protrusions137 ofhub132 engagecam track127 such thathub132 is movable alongcam track127 upon rotation ofcollar124.

Eachmicroneedle134 ofmicroneedle assembly130 includes alumen135 extending therethrough.Hub132 includes an openproximal end133 in communication with each oflumens135 ofmicroneedles134 such that the fluid “F” disposed withinfluid reservoir110 may flow intohub132, via openproximal end133 thereof, and intolumens135 ofmicroneedles134. Eachmicroneedle134 may define an angled, or beveleddistal end136 configured to facilitate passage of fluid therethrough, to facilitate penetratingbase140 and/or to facilitate puncturing of the patient's epidermis, although other configurations are contemplated. As can be appreciated, the number, configuration and dimensions ofmicroneedles134 may depend, at least in part, on the viscosity of the fluid to be delivered, the volume of fluid to be delivered, the chemical properties of the fluid to be delivered, and/or the desired delivery rate, or flow rate of the fluid into the patient's bloodstream.

Base140 of transdermalfluid delivery device100 is adapted to engageframe122 ofhousing120 atdistal end123aofframe122.Base140 may define a relatively thin membrane, e.g., a non-porous elastomeric membrane, or may define a more substantial foundation, e.g., a polymeric foundation, that includes a membrane disposed about a distal surface thereof. In either embodiment, it is envisioned thatbase140 is configured to fixedly engagedistal end123aofframe122 ofhousing120, while also being penetrable bymicroneedles134 ofmicroneedle assembly130. Further, it is contemplated thatbase140 be somewhat rigid to provide structural support to transdermalfluid delivery device100, but also be somewhat flexible to conform to the contours of the patient, to effect an efficient adhesion therebetween. In embodiments wherebase140 defines a foundation,base140 may include a plurality of perforatedmicroneedle channels142 defined therein corresponding to microneedles134 ofmicroneedle assembly130 to facilitate the penetration ofmicroneedles134 throughbase140.

With continued reference toFIG. 1, an adhesive or, more particularly, askin adhesive150, may be disposed on adistal surface144 ofbase140 of transdermalfluid delivery device100 for adhering transdermalfluid delivery device100 to a patient's epidermis, or skin, e.g., on a patient's arm. As such,skin adhesive150, e.g., a silicon adhesive, must have sufficient strength to retain transdermalfluid delivery device100 on the patient's arm and must be capable of withstanding rubbing from clothing, inadvertent bumping or brushing, movement of the arm, and/or other typical activity by the patient. Skin adhesive150 must also be sufficiently strong to inhibit dislodging or repositioning offluid delivery device100 upon rotation ofcollar124. However, on the other hand,skin adhesive150 must also permit removal of transdermalfluid delivery device100 from the patient's skin with minimal trauma and/or pain to the patient when treatment is complete.

A peelable cover, or backing155 may also be provided for maintaining the integrity of adhesive150, for protecting transdermalfluid delivery device100, e.g., for preventing contaminants from adhering to transdermalfluid delivery device100, and/or for inhibiting inadvertent adhesion of transdermalfluid delivery device100 prior to use or prior to proper positioning. As shown inFIG. 1, cover155 may initially be disposed over adhesive150 and may be peeled off or otherwise removed and discarded prior to the use of transdermalfluid delivery device100, e.g., prior to adhesion to the patient's skin.

Turning now toFIGS. 2 and 3, the use and operation of transdermalfluid delivery device100 will be described. Transdermalfluid delivery device100 may come pre-assembled, e.g., whereinfluid reservoir110 is pre-filled with the drugs and/or nutrients to be delivered and is engaged, or integrally formed withhub132 ofmicroneedle assembly134. In such an embodiment, transdermalfluid delivery device100 may be configured as a disposable device wherein the internal components of transdermalfluid delivery device100 are pre-sterilized. Accordingly, the user need only remove transdermalfluid delivery device100 from its packaging (not shown), removepeelable cover155, and adhere transdermalfluid delivery device100 to the patient's epidermis, e.g., to the patients upper arm. Since the fluid, e.g., the drugs and/or nutrients, as well as themicroneedle assembly130 are sealed within transdermalfluid delivery device100, viabase140, the risk of contaminants, e.g., bacteria, enteringfluid reservoir110 and/or contaminating themicroneedle assembly130 prior to, during, or after use, is substantially reduced. Thus, the risk of infection to the patient is substantially reduced. Alternatively, transdermalfluid delivery device100 may be configured, at least partially, as a sterilizable,reusable device100.

Initially, the surface of the patient's skin is cleaned and sterilized in accordance with known techniques. Next, in preparation for use,peelable cover155 is removed such thatskin adhesive150 is exposed. Lead bydistal surface144 ofbase140 having the exposedskin adhesive150 thereon, transdermalfluid delivery device100 is urged into contact with the patient's epidermis to securely adhere transdermalfluid delivery device100 thereto. At this point, as shown inFIG. 2,microneedle assembly130 is disposed in the initial, or retracted position withinhousing120, as indicated by theposition flange128 ofrotatable collar124 extending fromhousing120, and the fluid “F” is retained withinfluid reservoir110 by the penetrable membrane (not shown). In this retracted position, as discussed above,microneedles134 are fully disposed withinhousing120, e.g.,microneedles134 do not extend frombase140. This configuration, wherein transdermalfluid delivery device100 is disposed on the patient's skin prior to deployment of themicroneedles134 inhibits contamination ofmicroneedles134 prior to deployment through the patient's epidermis. In other words, the likelihood of contamination ofmicroneedles134 by the external environment is greatly reduced since, as will be described below,microneedles134 are deployed fromhousing120 directly into the patient's epidermis, with little or no contact with the external environment. Similarly, since transdermalfluid delivery device100 is adhered to the epidermis prior to any puncture wounds being created for insertion ofmicroneedles134, the likelihood of bacteria, disease, or contaminants entering the patient's blood stream is greatly reduced.

In order to begin treatment, e.g., to deliver fluid, drugs and/or nutrients transdermally into the patient's bloodstream, the user graspsflange128 ofrotatable collar124 to rotatecollar124 about longitudinal axis “X” and with respect tomicroneedle assembly130 from the position shown inFIG. 2, to the position shown inFIG. 3, e.g.,collar124 is rotated 180 degrees with respect tomicroneedle assembly130 in the clockwise direction (although it is envisioned thatcollar124 may alternatively be configured to rotate counterclockwise from the initial position or through other degrees of rotation (i.e., greater or less than 180 degrees). Accordingly, ascollar124 is rotated with respect tomicroneedle assembly130,protrusions137 ofhub132 ofmicroneedle assembly130 are cammed, or ramped alongcam track127 ofcollar124. As mentioned above, the pitch, or slope ofcam track127 causeshub132 to be translated distally along longitudinal axis “X” and with respect tohousing120 upon clockwise rotation ofcollar124. Upon rotation ofcollar124 to movemicroneedle assembly130 to the extended position, the penetrable membrane (not shown) is penetrated, allowing fluid “F” to flow intohub132 ofmicroneedle assembly130. Alternatively, the penetrable membrane or other selectively controlled barrier (not shown) may be penetrated or opened once themicroneedle assembly130 is moved to the extended position.

Distal translation ofhub132 ofmicroneedle assembly130 causesmicroneedles134 to move toward the extended position. When moved to the extended position, microneedles134 penetrate throughbase140, e.g., through perforatedmicroneedle channels142, and through the patient's epidermis. As mentioned above, the configuration ofmicroneedles134 facilitates penetration ofmicroneedles134 throughbase140 and through the epidermis. It is envisioned that transdermalfluid delivery device100 be configured such that, in the extended position, microneedles134 extend a sufficient distance frombase140 to fully penetrate the epidermis, e.g., by about 2 mm-3 mm. Further,housing120 may include a locking feature (not shown) for fixing the position ofcollar124, e.g., such thatmicroneedle assembly130 may be fixed, or locked in the extended position (and/or the retracted position). Additionally,microneedle assembly130 may be biased toward the retracted position or the extended position.

As can be appreciated, and as shown inFIG. 3, withmicroneedles134 disposed through the patient's epidermis, the fluid “F” withinfluid reservoir110 is permitted to flow fromfluid reservoir110, throughhub132 ofmicroneedle assembly130, throughlumens135 ofmicroneedles134 and outdistal tips136 ofmicroneedles134 into the patient's bloodstream. Transdermalfluid delivery device100 is left adhered to the skin, or epidermis, withmicroneedles134 penetrating therethrough until the desired amount of fluid “F” has been delivered to the patient. The specific amount of delivery time may depend on the configuration of transdermalfluid delivery device100, the fluids “F” to be delivered to the patient, and/or the specific treatment program being followed. Further, transdermalfluid delivery device100 may be configured for continuous delivery of fluids “F,” or may be configured for intermittent delivery of fluids “F,” e.g., upon depression offluid reservoir110.

In any configuration, once treatment is complete,collar124 is rotated back from the extended position, shown inFIG. 3, to the initial position, e.g.,collar124 is rotated 180 degrees in a counterclockwise direction about longitudinal axis “X,” shown inFIG. 2. Ascollar124 is rotated,hub132 ofmicroneedle assembly130 is ramped, or cammed alongcam track127, translatingmicroneedle assembly130 proximally along longitudinal axis “X” and with respect tohousing120. Asmicroneedle assembly130 is translated proximally,microneedles134 are retracted from the patient's epidermis and back throughbase140 to the retracted position, whereinmicroneedles134 are disposed withinhousing120.

Withmicroneedle assembly130 returned to the retracted position withinhousing120, transdermalfluid delivery device100 remains affixed to the patient's skin. More specifically, transdermalfluid delivery device100, which remains adhered to the patient's skin, covers the puncture wounds created bymicroneedles134. As can be appreciated, allowingmicroneedles134 to be retracted, or removed from the skin, without exposing the puncture wounds left behind to contamination from the external environment helps prevent infection and disease. Thus, the puncture wounds may be permitted to heal prior to removal of transdermalfluid delivery device100 from the skin. Once the wounds have healed, or once the likelihood of infection, disease, or bacteria entering the body through the puncture wounds is reduced to an acceptable level, transdermalfluid delivery device100 may be removed and discarded (or sterilized for repeated use).

Turning now toFIGS. 4-6, another embodiment of a transdermal fluid delivery device is shown identified byreference numeral200. Transdermalfluid delivery device200 is similar to transdermal fluid delivery device100 (FIG. 1) and generally includes afluid reservoir210, ahousing220, amicroneedle assembly230, and abase240.Fluid reservoir210 is adapted to retain a fluid “F,” e.g., medicaments, nutrients, or other treatment fluids, therein for delivery to the patient and may be configured similarly to fluid reservoir110 (FIG. 1), discussed above. Further,fluid reservoir210 is sealingly engaged tomicroneedle assembly230 and includes a pair ofguide channels212 disposed on opposing sides thereof. As in the previous embodiment, a penetrable membrane or selectively controlled barrier (not shown) may be disposed betweenfluid reservoir210 andmicroneedle assembly230, to inhibit the passage of fluid “F” therethrough prior to actuation offluid delivery device200.

Microneedle assembly230 may be configured similar to microneedle assembly130 (FIG. 1) and includes aproximal hub232 and a plurality ofmicroneedles234 extending distally fromhub232.Microneedles234 may define “V”-shaped, pointeddistal tips236, or may define any other suitable configuration that facilitates puncturing of the patient's epidermis and the delivery of fluids “F” into the patient's bloodstream.Microneedle assembly230 is axially translatable between a retracted position (FIG. 5), whereinmicroneedle assembly230 is fully disposed withinhousing220, and an extended position (FIG. 6), whereinmicroneedle assembly230 extends distally fromhousing220 and throughbase240 in a distal direction for penetration through a patient's skin.Microneedle assembly230 is engaged tofluid reservoir210 and includes a pair ofopposed apertures238 defined at opposing sides thereof in alignment withguide channels212 offluid reservoir210. Aprotrusion239 extends into each ofapertures238.Protrusions239 may be resiliently movable, or, alternatively, may be resiliently deformable from withinapertures238. More specifically,protrusions239 may be resiliently movable from a more occluding position withinapertures238, to a less occluding position, wherein protrusions are urged at least partially out ofapertures238. As will be described below, guidechannels212 offluid reservoir210,apertures238, andprotrusions239 are configured to permitmicroneedle assembly230, andfluid reservoir210 engaged thereto, to translate with respect tohousing220 between the retracted position and the extended position.

Base240, similar to base140 (FIG. 1), is configured to fixedly engagehousing220 at a distal end thereof. An adhesive250 may be disposed on adistal surface244 ofbase240 to adhere transdermalfluid delivery device200 to a patient's epidermis, or skin. As in the previous embodiment, adhesive250 must be sufficiently strong to inhibit dislodging and repositioning of transdermalfluid delivery device200 during the use and operations thereof. In particular, the adhesive must have sufficient strength to maintain the position of transdermalfluid delivery device200 during the transition ofmicroneedle assembly230 between the retracted and extended positions and during the latching and unlatching ofmicroneedle assembly230 in the retracted and/or the extended position. Further, apeelable cover255 may be disposed over adhesive250 for maintaining the integrity of adhesive250, for protecting transdermalfluid delivery device200 and/or for inhibiting inadvertent adhesion of transdermalfluid delivery device200 prior to use.

Housing220 of transdermalfluid delivery device200 differs from housing120 (FIG. 1) of transdermal fluid delivery device100 (FIG. 1) in that, instead of a rotatable collar124 (FIG. 1) configured for translatingmicroneedle assembly230 between the retracted position and the extended position,housing220 includes a pair ofguide posts222 disposed at opposing sides thereof to permitmicroneedle assembly230 to translate axially along longitudinal axis “X” and with respect tohousing220. More particularly, guideposts222 ofhousing220 are slidably positioned withinapertures238 ofhub232 ofmicroneedle assembly230 and guidechannels212 offluid reservoir210. Thus, as shown inFIG. 5, whenmicroneedle assembly230 is disposed in the retracted position withinhousing220, guide posts222 are only partially disposed throughapertures238 ofmicroneedle assembly230 and guidechannels212 offluid reservoir210. In order to movemicroneedle assembly230 to the extended position, as shown inFIG. 6,microneedle assembly230 andfluid reservoir210 are translated distally with respect tohousing220 such that guide posts222 are substantially disposed throughapertures238 ofmicroneedle assembly230 and guidechannels212 offluid reservoir210.

A pair ofsprings224, or other biasing members (not shown) may be provided for biasingmicroneedle assembly210 toward the retracted position. Thus, as shown inFIG. 5, springs224 are disposed aboutguide posts222 ofhousing220 to bias guide posts222 apart fromapertures238 and guidechannels212, thus biasingmicroneedle assembly210 toward the retracted position. Guide posts222 further definenotches226 disposed at distal ends thereof.Notches226 are shaped complementary toprotrusions239 ofmicroneedle assembly230 such that, as shown inFIG. 6, upon translation ofmicroneedle assembly230 to the extended position,protrusions239 are engageable withinnotches226 to retainmicroneedle assembly230 in the extended position, against the bias ofsprings224. More particularly, during translation ofmicroneedle assembly230 from the retracted position to the extended position, e.g., during translation ofguide posts222 throughapertures238 and guidechannels212,protrusions239 are urged fromapertures238 to the less occluding position to permit passage ofguide posts222 therethrough. However, upon achieving the extended position,notches226permit protrusions239 to resiliently return to the more occluding position. As such, when moved to the extended position,protrusions239 engagenotches226 to retainmicroneedle assembly230 in the extended position.

In order to releasemicroneedle assembly230, i.e., to permitmicroneedle assembly230 to return to the retracted position,microneedle assembly230 is translated proximally with sufficient force to disengageprotrusions239 fromnotches226, allowingmicroneedle assembly230 to return to the retracted position under the bias ofsprings224. Alternatively,protrusions239 may be formed from a resilient material having a specific, pre-defined period of resiliency. In other words, after a pre-determined length of time,protrusions239 may automatically disengage fromnotches226, returningmicroneedle assembly230 to the retracted position. Such a feature allows fluid “F” to be delivered to the patient for a pre-determined length of time, without requiring the patient to manually movemicroneedle assembly230 back to the retracted position. As such, the patient need not worry about remembering elapsed treatment time and/or may apply transdermalfluid delivery device200 during sleep, while the supply of fluids “F” is administered only during the pre-determined length of time. As can be appreciated, the pre-determined length of time may be determined by the type of fluids to be delivered, the physical characteristics of the patient and/or the specific treatment program being followed.Fluid delivery device200 may alternatively include a pull tab (not shown), release actuator (not shown), or other release structure for selectively disengagingprotrusions239 fromnotches226. Other releasable latching structures for retainingmicroneedle assembly230 in the extended position and/or the retracted position are also contemplated. The use and operation of transdermalfluid delivery device200 is otherwise similar to that described above with respect to transdermalfluid delivery device100.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying figures are non-limiting exemplary embodiments, and that the description, disclosure, and figures should be construed merely exemplary of particular embodiments. It is to be understood, therefore, that the present disclosure is not limited to the precise embodiments described, and that various other changes and modifications may be effected by one skilled in the art without departing from the scope or spirit of the disclosure. Additionally, it is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure, and that such modifications and variations are also intended to be included within the scope of the present disclosure. Accordingly, the subject matter of the present disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims.

Claims (9)

What is claimed is:

1. A transdermal fluid delivery device positionable on a patient's epidermis for delivering fluid into the patient's bloodstream, comprising:

a housing defining a longitudinal axis and having a proximal end and a distal end, the housing defining a passageway extending longitudinally therethrough and including a helical cam track disposed on an inner surface of the housing;

a fluid reservoir positionable within the passageway of the housing, the fluid reservoir adapted for retaining a fluid therein;

a base member positioned at the distal end of the housing; and

a microneedle assembly coupled to the fluid reservoir, the microneedle assembly including a hub and a plurality of microneedles extending distally from the hub, the hub including at least one protrusion extending outwardly therefrom that is engaged within the helical cam track, each microneedle of the plurality of microneedles including a lumen defined therethrough in communication with the fluid reservoir,

wherein rotation of the housing with respect to the microneedle assembly about the longitudinal axis of the housing in a first direction urges the at least one protrusion to move along the helical cam track, thereby translating the microneedle assembly longitudinally with respect to the housing from a retracted position, wherein the plurality of microneedles are disposed within the base member, to an extended position, wherein the plurality of microneedles are advanced distally to penetrate the base member and extend distally therefrom for puncturing the patient's epidermis and delivering the fluid into the patient's bloodstream, and

wherein rotation of the housing with respect to the microneedle assembly about the longitudinal axis of the housing in a second, opposite direction urges the at least one protrusion to move along the helical cam track, thereby translating the microneedle assembly longitudinally with respect to the housing from the extended position to the retracted position.

2. The transdermal fluid delivery device according toclaim 1, further comprising a latching mechanism for retaining the microneedle assembly in at least one of the retracted position and the extended position.

3. The transdermal fluid delivery device according toclaim 1, wherein the microneedle assembly is biased toward the retracted position.

4. The transdermal fluid delivery device according toclaim 1, wherein the microneedle assembly includes a first latch member and wherein the housing includes a second, complementary latch member such that, upon movement of the microneedle assembly to the extended position, the first and second latch members engage one another to retain the microneedle assembly in the extended position.

5. The transdermal fluid delivery device according toclaim 4, wherein at least one of the first and second latch members defines a pre-determined latching period, the at least one latch member configured to disengage the other latch member at the end of the pre-determined latching period to return the microneedle assembly under bias back towards the retracted position.

6. The transdermal fluid delivery device according toclaim 1, further comprising a skin adhesive disposed on a distal surface of the base member for adhering the base member to the patient's epidermis.

7. The transdermal fluid delivery device according toclaim 6, further comprising a peelable cover disposed about the skin adhesive to inhibit adhesion prior to removal of the peelable cover.

8. The transdermal fluid delivery device according toclaim 1, wherein, in the extended position, the plurality of microneedles extend distally from the base member by about 2 mm to about 3 mm.

9. The transdermal fluid delivery device according toclaim 1, wherein each microneedle of the plurality of microneedles includes a pointed distal end to facilitate at least one of penetrating the base member and puncturing the patient's epidermis.

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